As the key part of power supply equipment in electric vehicles, power battery box may lose effect due to random vibration of the electric vehicle. To effectively predict the strength of the structure of power battery box and the performance of the internal components in the environment of vibration, this paper uses union simulation of Hypermesh and ANSYS to analyze its intrinsic mode and the characteristics of responses caused by random vibration. In doing this, displacement, acceleration and equivalent stress nephogram are acquired, providing a basis for structure design and further optimization.